The invention relates to a laser system for medical removal of body tissue with a laser source for medical removal of body tissue by means of a laser beam within a predetermined treatment contour. The invention further relates to a method for operating such a laser system.
Classical surgical means to remove or shape soft or hard human tissue (including but not limited to the osseous (bone) tissue) are mechanical drills and saws. The advantage of these tools is that the surgeon has a very good tactile contact with the treated tissue providing feedback to the surgeon regarding the speed of the procedure and the depth of the drilled hole or the cut.
The mechanical means are disadvantageous because of the generated heat and thermal damage to the tissue as well as a smear layer that is left on the surface of the treated tissue. This leads to a delay in wound healing and compromised blood circulation. In order to minimize thermal damage to the tissue, the holes in the tissue are made by slowly drilling several holes of increasing diameter into the tissue, starting first with a small diameter drill. This makes the procedure very slow and also imprecise. Another disadvantage is the relatively great mechanical pressure that needs to be applied on the tissue in order to perform mechanical tissue removal. Disadvantageous are also the physical limitations with regard to achievable shape or size of the cuts and/or drilled holes. For example, it is not possible to achieve cuts in an exact zigzag pattern or other pattern that would be desirable e.g. for inserting implants in bone tissue in order to increase the bonding surface area.
In contrast to conventional mechanical methods, a manually performed non-contact laser surgery allows to ablate tissue in a shape that can be individually adapted to the clinical situation. Moreover, the laser allows arbitrary and sophisticated cut geometries with unprecedented preciseness. In addition, the cuts are clean and without the mechanically and thermally induced smear layer. However, the main disadvantage of laser surgery has been the difficulty in positioning the non-contact laser hand piece on the treated tissue and in obtaining a quick and reliable feedback with regard to the achieved depth of the laser cut or drilled hole. For this reason, laser-assisted surgery has not gained wide acceptance in the medical community.